Fix <rdar://problem/15858869> *all* objc accessors disabled in init methods, not just for self

This patch: 
 - Changes sema to set the "IsDirectPropertyAccess" on MemberRefExprs
   in inits/destructors that should be done directly because they are
   on the local object.
 - Removes the "SGF.AlwaysDirectStoredPropertyAccess" bool in SILGen,
   which was the source of the problem above and was otherwise problematic.

This will get a bit simpler when -enable-new-objc-properties rolls out. 


Swift SVN r12967

lib/SILGen/SILGen.cpp

@@ -34,8 +34,7 @@ SILGenFunction::SILGenFunction(SILGenModule &SGM, SILFunction &F)
   : SGM(SGM), F(F), LastInsnWithoutScope(0),
     B(createBasicBlock(), &InsertedInstrs),
     ReturnDest(CleanupLocation::getCleanupLocation(F.getLocation())),
-    NeedsReturn(false), AlwaysDirectStoredPropertyAccess(false),
-    CurrentSILLoc(F.getLocation()), Cleanups(*this)
+    NeedsReturn(false), CurrentSILLoc(F.getLocation()), Cleanups(*this)
 {
 }